'95 Volvo 940 -- 1) Interference engine? 2) Tranny fluid change?

The son (for whom you have helped me many times) is now in El Paso for a year. He has the chance to get a '95 Volvo 940 with B230 FD engine (4-cyl non-turbo) for the right price – free. Car had been sitting for two or three years. A recommended mechanic got it running OK (replaced fuel pump and a little other stuff), and son is proceeding piecemeal with other things to get it up to snuff.

  1. Sticker on timing belt cover indicates that belt is w/in Owner’s Manual mileage limit, but (as I recall) is 11 years old. Manual (which son is reading diligently) does not give time limit. Immediate question (to judge urgency of belt replacement): is this an interference engine? The recommended mechanic, the previous owner, and lots of on-line sources say no; Gates says yes. Anybody here have certain knowledge?

  2. Manual mentions some Maintenance book that son does not have. Does anybody here know the mileage limit for the timing belt (or where we can get the Maintenance book on-line)?

  3. Manual says to change tranny fluid at 40K miles, and we infer that it means “every 40K”. The mechanic who got it running said “fluid looks old, but recommend not to change it 'cuz that might bring problems.” I know this has been well-discussed here (drop-and-drain; clean/replace filter if feasible; do not flush); based on advice here, I get that done about every 30K miles. Does anybody here want to suggest NOT changing the fluid now? Should we be leery of the mechanic who is reluctant to change.

"The mechanic who got it running said “fluid looks old, but recommend not to change it 'cuz that might bring problems.”

Uh-oh!

“Should we be leery of the mechanic who is reluctant to change.”

Absolutely!
This guy is someone who apparently subscribes to Old Wives’ Tales.
I think that a real mechanic, with actual technical knowledge, would be preferable to this guy.

This source says your engine is not an interference. I would believe it since your mechanic and the previous owner agree:

http://www.volvoclub.org.uk/faq/EngineSealsBeltsVent.html#InterferenceEngines

PS…your mechanic just doesn’t want ro be blamed if new fluid dislodges old crud and causes problems, so he’s not necessarily a bad mechanic.

As far as I know, all or almost all Volvos are interference fit engines. If the car has the original belt it needs to be replaced along with the tensioner kit. The charts I have show it to be an interference fit engine; both naturally aspirated and turbocharged variants.

I do not agree with what you were told about changing the transmission fluid being the cause of any future problems; short of someone botching the fluid change of course.

What I would suggest is that before spending any money on a timing belt kit that the transmission pan be dropped and cleaned along with a fluid change.

With the pan off one can eyeball the bottom of the pan and note if there are any excessively large pieces of metallic debris or excessive sludge. Either one could mean a transmission issue cropping up and it’s better to determine this before wading into the time and expense of a timing belt job.

I don’t blame an independent mechanic for being leery of changing transmission fluid. It is not that he is going to ruin your transmission, he is afraid of being accused of ruining your transmission. Most car owners don’t even think of changing the fluid until the trans is starting to slip and then when the trans goes, they blame the mechanic.